Improvement in pressure-gauges for gas-fitters



R. B. DONALDSON.

Pressure Gage, No. 66,221 Patented July 2, 1867.

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R. B. DONALDSON OF WASHINGTON, DISTRICT OF COLUMBIA.

. Letters Patent No. 66,227, and Jul 2, 1867 IMPROVEMENT IN PRESSURE-GAUGES FOB. GAS-PETERS.

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'iO ALL WHOM IT MAY CONCERN:

Be it known that I, R. B. DONALDsoN, of Washington, District of Columbia, have invented a. new and improved Pressure-Gauge for the use of Gas-Fitters and others; and I do hereby declare that the following is a full and exact description thereof, reference being had to the accompanying drawings,'and -to the letters of reference marked thereon.

My invention consists in constructing a tube wit-h an expanded base or. reservoir, thebottom of which is formed of India rubber of sufficient elasticity to allow of its displacing, when pressure is applied from below, as much mercury (with which the reservoir is filled) as will fill the tube to the top. The degree of pressure is indicated by the elevation of the mercury in the tube, which is provided with aglassface and a scale marked in any convenient manner. r

To enable others skilled in the art to make and use my invention, I will proceed to describe its construction and operation. v

The base is of metal, as shown at A, Figure 1, with a chamber or reservoir, 11, with an elastic bottom, 0, and is filled with mercury. At the lower end is the socket a, by which the gauge is attached to the pipe to be tested. The top of the reservoir is formed by the shank or lower end of the tube B, and is of wood, one half of which, above 01, is cut away longitudinally, and its place supplied with a plateglass face cemented thereto, and clamped firmly by the metal case e, as shown in cross-sections Figures 2 and 3.

Figure 4 is a view of the top and the cap Q, with a packing of India rubber on the under side, which is tightened upon the top of the tube,by means of the thumb-screw f, to prevent the loss of the mercury during transportation. .lVhen in use the cap is loosened. The calibre of the tube being small, a moderate riseof the diaphragm c wilLforce the mercury to the top, the degree of pressure being indicated by the position of the mercury, seen through the glass face, of the tube, and canbe marked, it necessnry, by a sliding hand or, index, or in any other convenient manner.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent,-is, not the tube, formedpart-ly of wood, vuleanite, or other analogous material, and with a glass face cemented thereto, and secured bya clamp or clamps, as described, as that is the invention of Emmett Quinn, for which he designs making application for Letters Patent, and his claim to the invention of which I hereby recognize; but

A gas-fitters pressure-gauge,constructed by combining the base 'A, containing the reservoir 6, elastic bottorn c, and socket a, with the shank of the tube B, in the manner and for the purpose described.

' R. B. DONALDSON.

Witnesses:

J. D. CLARK, EMMETT QUINN. 

